1. Field of the Invention
This invention relates generally to optical digital circuits, including latches and logic gates. More particularly, it relates to optical digital circuits based on devices such as vertically lasing semiconductor optical amplifiers (VLSOAs).
2. Description of Related Technologies
Digital electronics has revolutionized technology. Generally, in digital electronics, basic “building block” electronic digital circuits are combined to create more complicated and useful circuits, such as computer processors. These basic “building block” digital circuits include such well-known circuits as a NOT gate, a NOR gate, an OR gate, an AND gate, a NAND gate, a latch, and an astable multivibrator. Each of these electronic digital circuits is well known in the art.
However, the speed of electronic digital circuits is limited. For example, typical electronic digital circuits comprise transistors, which turn on and off. The transitions between on and off for each transistor takes time. Thus, electronic digital circuits limit a system's speed. In general, optical systems are capable of greater speed than electronic systems. Therefore, it is desirable to have optical digital circuits.
In addition, the use of electronic digital circuits in optical systems has drawbacks. For example, optical communication systems are capable of quickly moving large amounts of data. Frequently, it is desirable to use digital circuits in these optical communication systems. When electronic circuits are used in optical systems, the optical signal is converted into an electronic signal. After processing by the electronic circuits, the signal is re-converted to an optical signal. This conversion and re-conversion requires extra components, which add cost and size to the system. Further, the use of electronic components limits the speed of the system to the speed of the electronics, rather than allowing the system to take advantage of the speed of optical circuits.